Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 113, NWS Flagstaff, AZ

July 27, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 27, 2021, 8:06 PM MST for Coconino County, Arizona. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 27, 2021, 8:06 PM MST (03:06 UTC)
Expired: Jul 27, 2021, 11:15 PM MST
In force: 3 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Coconino County, AZ

The radar

The Flagstaff radar (KFSX), 68 km from the middle of the area, began a volume at 03:06 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where	Remark
Jul 27, 8:25 PM MST	FLASH FLOOD	Twin Arrows, AZ	TWIN ARROWS DIRECTOR OF SECURITY REPORTED THAT MAJOR PORTIONS OF THE PROPERTY WERE FLOODED AND THAT FLOOD WATERS SENT DEBRIS ALL OVER THE ROADS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 3.1 hours before the alert went out and 54 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 218 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 1872 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -8 m²/s²
0-3 km storm-relative helicity: 29 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

041 
WGUS55 KFGZ 280306
FFWFGZ
AZC005-280615-
/O.NEW.KFGZ.FF.W.0113.210728T0306Z-210728T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
806 PM MST Tue Jul 27 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Coconino County in north central Arizona...

* Until 1115 PM MST.

* At 805 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts of 0.5 to 1.5 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Life-threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life-threatening flash flooding of low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  Twin Arrows, Angell, Two Guns, Rimmy Jims, Sunrise, Leupp and 
  Navajo Reservation.

This includes the following highways...
	State Route 99 between mile markers 65 and 71.
	Interstate 40 between mile markers 213 and 235.

This includes the following streams and drainages...
  Babbitt Wash, Diablo, Canyon, Little Colorado River, Yellow Jacket 
  Canyon, Anderson Canyon, Wallace Canyon, Canyon Diablo Wash, Padre 
  Canyon, Little Roden Wash, San Francisco Wash and Youngs Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3507 11134 3532 11143 3544 11120 3526 11091
      3508 11101 3504 11122

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Humphreys

2 follow-up statements

007 
WGUS75 KFGZ 280448
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
948 PM MST Tue Jul 27 2021

AZC005-280615-
/O.CON.KFGZ.FF.W.0113.000000T0000Z-210728T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
948 PM MST Tue Jul 27 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM MST THIS 
EVENING FOR COCONINO COUNTY...

At 947 PM MST, heavy rain had moved out of the the warned area, 
however flash flooding is expected to remain a threat while water
recedes.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  Twin Arrows, Angell, Two Guns, Rimmy Jims, Sunrise, Leupp and 
  Navajo Reservation.

This includes the following highways...
	State Route 99 between mile markers 65 and 71.
	Interstate 40 between mile markers 213 and 235.

This includes the following streams and drainages...
  Babbitt Wash, Diablo, Canyon, Little Colorado River, Yellow Jacket 
  Canyon, Anderson Canyon, Wallace Canyon, Canyon Diablo Wash, Padre 
  Canyon, Little Roden Wash, San Francisco Wash and Youngs Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3507 11134 3532 11143 3544 11120 3526 11091
      3508 11101 3504 11122

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Humphreys

725 
WGUS75 KFGZ 280612
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
1112 PM MST Tue Jul 27 2021

AZC005-280622-
/O.EXP.KFGZ.FF.W.0113.000000T0000Z-210728T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
1112 PM MST Tue Jul 27 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1115 PM MST THIS EVENING FOR 
COCONINO COUNTY...

The heavy rain has ended in the Twin Arrows area. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 3507 11134 3532 11143 3544 11120 3526 11091
      3508 11101 3504 11122

$$

TPS

The office that day

Everything else NWS Flagstaff, AZ issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 27, 7:28 PM MST	Special Weather Statement	FGZ		32 min
Jul 28, 11:46 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 28, 3:07 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 28, 3:35 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 28, 4:35 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	2 hr
Jul 28, 4:43 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila, Navajo	3 hr

Nearby

Flash Flood Warnings in Arizona, 2021 Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.